1. Field of the Invention
The present invention relates to decorative buttons to be provided in the surface of an automotive seat and, more particularly, to decorative buttons to be provided in the surface of a trim cover assembly which forms a part of an automotive seat and comprises a lamination of a top cover member, a wadding and a wadding cover.
2. Description of the Prior Art
A conventional automotive seat is provided with a plurality of decorative buttons which are designated by (12) (12)--in FIG. 1. Each of such conventional decorative buttons (12)(12)--is constructed in the manner shown in FIG. 2. In particular, each button (12) is produced in the following manner: a button core member (1) is inserted between a top cover member (2) and a wadding (3) formed of foam material; and then, the peripheral portions of the core member (1) are pressed and heated in a round manner by means of high frequency welding together with a reinforcing member (5) to be welded integrally with the surrounding members, with a deep-valley-shaped recess (6) being formed in the surface of the top cover member (2).
In FIG. 3, there is illustrated a method for manufacturing the above-mentioned buttons. That is, the top cover member (2), button core member (1), wadding (3), wadding cover (4) and reinforcing member (5) are sequentially placed on one another, and then they are pressed against one another and heated by means of a high frequency welder lower mold (7) and an upper electrode (8) to be integrally welded to one another. The welder lower mold (7) is formed at its top end with a recessed portion (9) having an inside diameter substantially equal to the outside diameter of the button core member (1). In FIG. 3, (10) designates a circular peripheral portion for welding.
In this way, the welder lower mold (7) cooperates with the upper electrode (8) to weld the top cover member (2), wadding (3), wadding cover (4) and reinforcing member (5) into one united body along the periphery of the button core member (1) and at the same time to form a deep-valley-shaped recess (10) in the surface of the top cover member (2) along the periphery of the button core member (1) so that the button (12) is formed by the portion enclosed by this recess (Japanese Patent Publication No. 48207 of 1982).
FIG. 4 illustrates another conventional example in which a button core member (1) is formed with an integral hook portion (1a). In this case, a wadding (3), a wadding cover (4), a reinforcing member (5) and an upper electrode (8) are respectively formed with through-bores (3a), (4a), (5a), (8a) through which the above-mentioned hook portion (1a ) can be passed.
However, in the former prior art wherein the button core member (1) is interposed between the top cover member (2) and wadding (3) and a configuration formed by such core member (1) is enveloped by the top cover member (2) so as to produce the decorative button, the rigidity of the button core member (1) can not be absorbed by the top cover member (2) only. Therefore, when touched, the thus-formed decorative button provides a harder touch over the remaining portions of the top cover member (2) to produce a strange feeling.
Also, in the latter conventional case wherein the button core member (1) is provided with the hook portion (1a), there is a trouble of forming the bores (3a), (4a), (5a) in the wadding (3), wadding cover (4) and reinforcing member (5), respectively.
In addition, in both of the above-mentioned prior art decorative buttons, since the button core member (1) is first placed on the top cover member (2) and then the wadding (3), wadding cover (4) and reinforcing member (5) are to be put on one another sequentially, there is a possibility of the button core member (1) being out of position. And, because the button core member (1) is hard to see, the positioning of the welder lower mold (7) and upper electrode (8) is difficult when they are used for application of pressure and heating.